POSTWEANING GAIN AND FEED EFFICIENCY OF CROSSBRED BULLS, STEERS AND HEIFERS FROM CHAROLAIS, SIMMENTAL AND LIMOUSIN SIRES MATED TO HEREFORD, ANGUS AND SHORTHORN DAMS
Postweaning gain and feed efficiency results are reported from an evaluation of crossbred calves sired by Charolais, Simmental and Limousin bulls and born to Hereford, Angus and Shorthorn cows in 48 herds located throughout the Canadian Prairie Provinces. Bull, steer and heifer calves were weaned at approximately 7 mo of age and transported to the Brandon or the Lacombe Research Stations where their performance was measured during a 112-d postweaning test period in which male calves were fed a high-energy feedlot diet and heifers were developed as breeding females on a lower energy diet. The data, which did not represent all sire breeds or sexes in all station years, were analyzed in eight separate data sets for gain and five for feed efficiency. Interpretation is based on paired comparisons of breed crosses within data set. In general, Limousin-sired male calves gained an average of 14.0 kg less than Charolais-sired and 9.6 kg less than Simmental-sired male calves from comparable dams, while Charolais-sired and Simmental-sired male calves performed equally. The same breed-of-sire pattern was apparent in heifer calves fed a lower energy diet, but the effects were smaller and were significant less often. Breed-of-dam effects were apparent for on-test weight, but not for gain during the test period. There were no consistent breed-of-sire differences in feed conversion ratio. The cost to the feeder of the slower gain exhibited by the Limousin-sired calves in this experiment could be offset by the lower calf purchase weight, depending on the premium, if any, paid on the price per kg for the lighter calves. Key words: Beef cattle, breed comparison, post-weaning growth, feed efficiency